Constructs a object implementing the StoreQuery interface.

There are two options for calling it:

function O.query()

Returns a blank StoreQuery object, ready for the query to be generated programmatically.

function O.query(string)

Returns a StoreQuery object generated by parsing the string as a query, exactly the same as a query in the Haplo user interface.

See the in-application help for details on the query syntax.